A technology of performing correction processing for image data generated by optically reading a document with a reading apparatus, such as a scanner, has been known. For example, JP-A-2006-339874 discloses a technology of changing a pixel value indicative of a specific color in an image into a pixel value indicative of white. According to this technology, a color palette is displayed on a multifunction device color liquid crystal panel, and an instruction of the specific color is received from a user.